Paint spray booths are commonly found in production lines for vehicle bodies and parts. A vehicle body is transported through a paint spray booth where paint is applied to the body and subsequently dried. The paint may be applied by human operators or mechanically by automated equipment. During this painting process some of the paint may not be applied to the vehicle, but rather appears as overspray in the booth's atmosphere. This overspray must be removed from the paint spray booth to keep it from falling back on the painted vehicle or from being inhaled by the operators of the equipment.
The paint overspray is typically removed by providing an air flow from a supply plenum above the paint spray booth, through the paint spray booth and out to gas scrubber equipment which removes paint particles from the exhaust gas. It is desirable to maintain the air flow passing over the vehicle being painted turbulent-free. This ensures the air flow does not disturb the paint on the vehicle. The minimizing of the air flow about the vehicle increases the transfer efficiency onto the vehicle body. High air flow volumes in that location have a tendency to disrupt the transfer efficiency of the paint being applied onto the vehicle body. Moreover, by reducing the air flow at the central portion the overall volume of air is reduced. All of the air passing through the paint spray booth must be treated with a complicated process, and by reducing the air flow volume, the abatement requirements for cleaning the air are correspondingly reduced. At the same time however, it is also desirable to keep the air flow passing over the painting equipment operators at a higher velocity to prevent the operators from inhaling paint. Even with automated applicators, it is desirable to have the air flow velocity at the sides of the booth as high as possible to maximize the removal of the paint-laden air. The operator or automated applicator are typically in the paint spray booth alongside the vehicle to be painted.
Also in the prior art, roll filters in the plenum extended laterally across the width of the paint spray booth. Those roll filters were typically separated by upstanding frames extending above the height of the filter. The flames disrupted the flow of air from the supply plenum and into the paint spray booth, creating localized turbulent swirling portions in the air flow. As described above, the air flow in a paint spray booth is preferably kept as close to laminar as is possible. As such, the prior art supply plenums having frames disposed within the air flow and extending laterally across the paint spray booth had undesirable characteristics.